Digital three-dimensional object manufacturing, also known as digital additive manufacturing, is a process of making a three-dimensional solid object of virtually any shape from a digital model. Three-dimensional object printing is an additive process in which one or more ejector heads deposit material to build up a part. Material is typically deposited in discrete quantities in a controlled manner to form layers that collectively form the part. The initial layer of material is deposited onto a substrate, and subsequent layers are deposited on top of previous layers. The substrate is supported on a platform that can be moved relative to the ejection heads so each layer can be printed; either the substrate is moved via operation of actuators operatively connected to the platform, or the ejector heads are moved via operation of actuators operatively connected to the ejector heads. Three-dimensional object printing is distinguishable from traditional object-forming techniques, which mostly rely on the removal of material from a work piece by a subtractive process, such as cutting or drilling.
In a conventional three-dimensional object printing system, six different build materials are typically used to print three-dimensional objects in full color. In many three-dimensional object printing systems, full color requires a cyan build material, a yellow build material, a magenta build material, a black build material, a white build material, and a clear build material. In order to print three-dimensional objects with different material properties (e.g. hardness, elasticity, plasticity, fracture, or rheology), a full set of build materials are required for each level of the material property. For example, a printing system that is enabled to print three-dimensional objects in full color and with variations in hardness usually requires a fairly large number of build materials and a correspondingly large number of ejectors or ejector heads. For example, a printing system that is enabled to print three-dimensional objects in full color and with six variations in hardness would require build materials having six different levels of hardness in each of the six different colors (i.e. thirty-six different build materials). As a result, the cost of such a printing system can be very high.
Therefore, a printing system that could provide a full color gamut, as well as variable hardness without a substantial increase in the number of different build materials required, would be beneficial. Implementing such a printing system without other increases in cost or hardware complexity would also be advantageous.